Visibility Graph

Graph degree distribution, clustering, small-worldness
topologicaldim Network6 metrics

What It Measures

What kind of network your time series becomes when you connect every pair of points that can "see" each other over the intervening values.

Treats the signal as a landscape and draws an edge between two time points whenever no intermediate value blocks the line of sight between them. Tall peaks see far; valleys are hidden. The resulting graph's degree distribution, clustering, and assortativity encode the signal's dynamical class. Periodic signals produce regular graphs. Chaotic signals produce scale-free networks. Random signals produce specific power-law exponents predicted by theory.

Metrics

assortativity

Do high-degree nodes connect to other high-degree nodes (positive), or to low-degree ones (negative)? Rössler Hyperchaos (0.76) is strongly assortative: its tall peaks cluster together. LIGO Livingston (0.54) also shows this pattern. Lotka-Volterra (-0.57) is strongly disassortative: its predator-prey oscillations create peaks that connect to valleys, not to each other. Logistic Period-2 (-0.50) alternates high-low, producing the same disassortative pattern.

avg_clustering_coeff

How interconnected are each node's neighbors? Rainfall (0.85) has the highest clustering -- its rain events create local clusters of mutually visible points. Neural Net Pruned (0.83) and Sensor Event Stream (0.81) show similar cliquish structure. Devil's Staircase (0.0) has zero clustering because its flat plateaus followed by jumps create a graph where neighbors never see each other.

degree_exponent_gamma

Power-law exponent of the degree distribution. DNA SARS-CoV-2 (2.94) has the steepest decay -- most nodes have low degree, with rare high-degree hubs. Circle Map QP (2.78) and Rule 30 (2.77) follow. For iid random data, the NVG degree distribution is exponential (Lacasa et al. 2008), so the power-law exponent from a forced fit is not theoretically meaningful in that regime — but deviations across signals still reveal structural differences.

max_degree

The most-connected node in the graph. Lotka-Volterra (690) has an extreme hub -- its largest predator-prey peak can see across 690 other time points. Rainfall (587) and Van der Pol (540) also produce high-visibility peaks. Devil's Staircase has max_degree = 2, meaning no point can see beyond its immediate neighbors.

Atlas Rankings

assortativity
SourceDomainValue
Rössler Hyperchaoschaos0.7641
LIGO Livingstonastro0.5444
Clipped Sinewaveform0.4930
···
Lotka-Volterrabio-0.5740
Logistic r=3.2 (Period-2)chaos-0.4966
Hodgkin-Huxleybio-0.4472
avg_clustering_coeff
SourceDomainValue
Rainfall (ORD Hourly)climate0.8524
Neural Net (Pruned 90%)binary0.8301
Sensor Event Streamexotic0.8123
···
Constant 0xFFnoise0.0000
Constant 0x00noise0.0000
Devil's Staircaseexotic0.0000
degree_exponent_gamma
SourceDomainValue
DNA SARS-CoV-2bio2.9429
Circle Map Quasiperiodicchaos2.7779
Rule 30exotic2.7720
···
Constant 0xFFnoise0.0000
Constant 0x00noise0.0000
Devil's Staircaseexotic0.0000
degree_r_squared
SourceDomainValue
Earthquake Depthsgeophysics0.9743
Poker Handsexotic0.9630
Collatz Stopping Timesnumber_theory0.9613
···
Constant 0xFFnoise0.0000
Constant 0x00noise0.0000
Devil's Staircaseexotic0.0000
graph_density
SourceDomainValue
Sine Wavewaveform0.1564
Lotka-Volterrabio0.1451
Duffing Oscillatorchaos0.1366
···
Constant 0xFFnoise0.0000
Constant 0x00noise0.0000
Devil's Staircaseexotic0.0020
max_degree
SourceDomainValue
Lotka-Volterrabio690.4000
Rainfall (ORD Hourly)climate587.4000
Van der Pol Oscillatorexotic539.8000
···
Constant 0xFFnoise0.0000
Constant 0x00noise0.0000
Devil's Staircaseexotic2.0000

When It Lights Up

Visibility Graph is the atlas's best tool for separating oscillatory dynamics by their waveform shape. The assortativity metric spans from -0.57 to +0.76 across the atlas, a range no other metric covers, and it cleanly separates predator-prey / period-doubling dynamics (negative) from hyperchaotic / bursty dynamics (positive). The clustering coefficient uniquely identifies bursty event streams and rainfall as topologically cliquish -- a property invisible to spectral or distributional geometries.

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